Ultrasonic-assisted extraction of pigment from natural green cotton

The goal of this research work is to establish a method for the relative quantitative analysis on the pigment in natural green cotton,and on this basis,the paper made a quantitative analysis on the effects obtained by ultrasonic-assisted extraction and normal extraction separately.The UV spectral character of the pigment of natural green cotton in ethanol solution by UV spectrophotometry was studied.It was found that there is a linear relationship between the absorption value and pigment concentration at 360 nm,R2=0.999 2.The established relative quantitative analysis method was used to investigate the influence of temperature,time and the volume of the solution on the extraction,and comparison results showed that the efficiency of ultrasonic-assisted extraction was significantly higher than that of normal extraction at the same conditions.The efficiency of ultrasonic-assisted extraction of natural green cotton pigment for 20 min was equivalent to that of ordinary extraction for 5 hours,thus shortening the test cycle of the pigment.Research found that the color of pigment solution of natural green cotton darkens with the increase of pH value,and has intensive pH value dependence.